Gasification is a process that converts hydrocarbons such as coal, petroleum coke (petcoke), and biomass to a synthesis gas (syngas), which can be further processed to produce chemicals, fertilizers, liquid fuels, hydrogen, and electricity. Gasification is a flexible, commercially proven, and efficient technology that produces the building blocks for a range of high value products from a variety of low value feedstocks.
In general in gasification processes, a hydrocarbon feedstock is injected with oxygen and steam into a high temperature pressurized reactor until the chemical bonds of the feedstock are broken. The resulting reaction produces the syngas. The syngas is then cleansed to remove impurities such as sulfur, mercury, particulates, and trace minerals. (Carbon dioxide can also be removed at this stage.) The clean syngas is then used to make either a single product such as fertilizer or multiple products such as hydrogen, steam, and electric power.
Gasification is among the cleanest and most efficient technologies for the production of power, chemicals and industrial gases from hydrocarbon feedstocks, such as coal, heavy oil, and petroleum coke. Simply stated, gasification converts hydrocarbon feedstocks into clean synthesis gas, or syngas, composed primarily of hydrogen (H2) and carbon monoxide (CO). In a gasification plant, the feedstock is mixed with oxygen (O2) and they are injected into a gasifier. Inside the gasifier, the feedstock and the O2 are subjected to a high-temperature and a high-pressure. As a result, the feedstock and the O2 break down into syngas.
In addition to H2 and CO, the syngas contains other gases in small quantities, such as ammonia, methane and hydrogen sulfide (H2S). As much as 99% or more of the H2S present in the syngas can be recovered and converted to elemental sulfur form and used in the fertilizer or chemical industry. Ash and any metals are removed in a slag-like state, and the syngas is cleansed of particulates. The clean syngas is then used for generating electricity and producing industrial chemicals and gases.
Gasification allows refineries to self-generate power and produce additional products. Thus, gasification offers greater efficiencies, energy savings, and a cleaner environment. For example, some gasification plants may convert petroleum coke and refinery wastes into electricity and steam, making the refinery entirely self-sufficient for its energy needs and significantly reducing waste and coke handling costs. For these reasons, gasification has increasingly become popular among refiners worldwide. Currently, there are several hundred gasification plants in operation worldwide.
For these reasons, a need has been recognized for a control system capable of controlling various critical components of the gasification plant. A control system should improve the reliability of the gasification plant by reducing gasifier shut downs and maximizing run-time. Also, an ideal control system should reduce wear and tear of the gasifier and other associated components.